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author | Tang Junhui <tang.junhui@zte.com.cn> | 2018-03-18 17:36:19 -0700 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-03-18 20:15:20 -0600 |
commit | bc082a55d25c837341709accaf11311c3a9af727 (patch) | |
tree | 4a3bf3286ad08651cda3698ceff5799d4b7d9b87 /drivers/md | |
parent | 7e027ca4b534b6b99a7c0471e13ba075ffa3f482 (diff) | |
download | linux-stable-bc082a55d25c837341709accaf11311c3a9af727.tar.gz linux-stable-bc082a55d25c837341709accaf11311c3a9af727.tar.bz2 linux-stable-bc082a55d25c837341709accaf11311c3a9af727.zip |
bcache: fix inaccurate io state for detached bcache devices
When we run IO in a detached device, and run iostat to shows IO status,
normally it will show like bellow (Omitted some fields):
Device: ... avgrq-sz avgqu-sz await r_await w_await svctm %util
sdd ... 15.89 0.53 1.82 0.20 2.23 1.81 52.30
bcache0 ... 15.89 115.42 0.00 0.00 0.00 2.40 69.60
but after IO stopped, there are still very big avgqu-sz and %util
values as bellow:
Device: ... avgrq-sz avgqu-sz await r_await w_await svctm %util
bcache0 ... 0 5326.32 0.00 0.00 0.00 0.00 100.10
The reason for this issue is that, only generic_start_io_acct() called
and no generic_end_io_acct() called for detached device in
cached_dev_make_request(). See the code:
//start generic_start_io_acct()
generic_start_io_acct(q, rw, bio_sectors(bio), &d->disk->part0);
if (cached_dev_get(dc)) {
//will callback generic_end_io_acct()
}
else {
//will not call generic_end_io_acct()
}
This patch calls generic_end_io_acct() in the end of IO for detached
devices, so we can show IO state correctly.
(Modified to use GFP_NOIO in kzalloc() by Coly Li)
Changelog:
v2: fix typo.
v1: the initial version.
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md')
-rw-r--r-- | drivers/md/bcache/request.c | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 7aca308bee5b..5c8ae69c8502 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -986,6 +986,55 @@ static void cached_dev_nodata(struct closure *cl) continue_at(cl, cached_dev_bio_complete, NULL); } +struct detached_dev_io_private { + struct bcache_device *d; + unsigned long start_time; + bio_end_io_t *bi_end_io; + void *bi_private; +}; + +static void detached_dev_end_io(struct bio *bio) +{ + struct detached_dev_io_private *ddip; + + ddip = bio->bi_private; + bio->bi_end_io = ddip->bi_end_io; + bio->bi_private = ddip->bi_private; + + generic_end_io_acct(ddip->d->disk->queue, + bio_data_dir(bio), + &ddip->d->disk->part0, ddip->start_time); + + kfree(ddip); + + bio->bi_end_io(bio); +} + +static void detached_dev_do_request(struct bcache_device *d, struct bio *bio) +{ + struct detached_dev_io_private *ddip; + struct cached_dev *dc = container_of(d, struct cached_dev, disk); + + /* + * no need to call closure_get(&dc->disk.cl), + * because upper layer had already opened bcache device, + * which would call closure_get(&dc->disk.cl) + */ + ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO); + ddip->d = d; + ddip->start_time = jiffies; + ddip->bi_end_io = bio->bi_end_io; + ddip->bi_private = bio->bi_private; + bio->bi_end_io = detached_dev_end_io; + bio->bi_private = ddip; + + if ((bio_op(bio) == REQ_OP_DISCARD) && + !blk_queue_discard(bdev_get_queue(dc->bdev))) + bio->bi_end_io(bio); + else + generic_make_request(bio); +} + /* Cached devices - read & write stuff */ static blk_qc_t cached_dev_make_request(struct request_queue *q, @@ -1028,13 +1077,8 @@ static blk_qc_t cached_dev_make_request(struct request_queue *q, else cached_dev_read(dc, s); } - } else { - if ((bio_op(bio) == REQ_OP_DISCARD) && - !blk_queue_discard(bdev_get_queue(dc->bdev))) - bio_endio(bio); - else - generic_make_request(bio); - } + } else + detached_dev_do_request(d, bio); return BLK_QC_T_NONE; } |